1. Field of the Invention
The present invention relates to the malfunction detection technologies, and it particularly relates to a malfunction detection method for detecting malfunctions and faults caused in apparatus and a base station apparatus utilizing the same.
2. Description of the Related Art
When a base station apparatus breaks down in a radio communication system such as a personal handyphone system, the access to a terminal apparatus via said base station apparatus is disabled. Thus, the prolonged failure of a base station apparatus is generally unacceptable for the telecommunication companies. For this reason, the base station apparatus is required to have durability and self-test capability. If the failure can be promptly detected by a self-diagnosis function, the telecommunication company can prevent the prolonged failure of a base station apparatus by replacing the faulty base station apparatus anew or the like. As a method for detecting malfunctions of apparatus, particularly for detecting faults in a plurality of antennas, the VSWR (Voltage Standard Wave Ratio) method has been executed conventionally. In the VSWR method, the reflected wave is detected from each antenna and the detected signal is converted to DC voltage so as to detect the level of the reflected wave. And if the value of the reflected wave level exceeds a predetermined level value, it is judged that a malfunction is caused in the antenna (See reference (1) in the following Related Art List, for instance).
Related Art List
    (1) Japanese Patent Application Laid-Open No. Hei09-83418.
In order to execute the VSWR method, the base station apparatus needs to be equipped with a circuit for executing the VSWR method in addition to the circuits for executing the communication functions. Thus, the overall size of circuits is enlarged and the power consumption increases. Also, the cost for the base station apparatus increases. In general, the VSWR method is used to detect malfunctions of a transmitter circuit and therefore cannot detect malfunction of a receiver circuit.